Maximum Zero Fuel Weight

Maximum Zero Fuel Weight (MZFW) is the maximum permissible weight of an aircraft with everything loaded (passengers, cargo, crew, catering, water) except usable fuel. It is a structural limit that protects the wing root from excessive bending loads.

• Payload is limited by MZFW minus Operating Empty Weight (OEW)
• Fuel stored in the wings actually reduces wing bending stress (weight is carried where lift is generated)
• MZFW is a fixed structural limit certified during type certification
• Exceeding MZFW concentrates too much weight in the fuselage relative to wing fuel
• Example: B737-800 MZFW ≈ 61,689 kg, MTOW ≈ 79,016 kg — difference is maximum usable fuel at MTOW